1. Technical Field
The present invention provides a dye compound, a method of producing a dipyrromethene metal complex compound, a method of producing a dye multimer, a substituted pyrrole compound, a colored curable composition, a color filter, a method of producing a color filter, a solid-state image sensor, and a liquid crystal display device.
2. Related Art
A pigment dispersion method is one of the methods of producing a color filter used in liquid crystal display devices or solid-state imaging sensors, and one of such pigment dispersion methods is a method of producing a color filter by photolithography using a colored curable composition prepared by dispersing a pigment in a curable composition of various kinds. Specifically, a film is formed on a support by applying a colored curable composition thereon with a spin coater, roll coater or the like, and drying the applied composition. Then, the film is exposed to light in a patterned manner and developed, whereby colored pixels are formed. A color filter is produced by repeating the process for a number of times corresponding to the number of colors to be used in the color filter.
The above method has been widely appreciated as a suitable method of producing color filters for color displays, because the composition is stable with respect to light or heat due to the use of a pigment, and sufficient positional accuracy is secured by performing patterning by photolithography.
In the field of color filters used for solid-state image sensors such as CCDs, use of a dye instead of a pigment has been studied with the aim of achieving a high resolution (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 6-75375). However, dye-containing colored curable compositions are accompanied by new problems as set forth below.
(1) dyes, being in a state in which molecules thereof are dispersed, exhibit inferior light fastness or heat fastness compared with pigments, which are typically an aggregation of molecules.
(2) dyes, being in a state in which molecules thereof are dispersed, exhibit inferior solvent resistance compared with pigments, which are typically an aggregation of molecules.
(3) dyes tend to exhibit interaction with other components in the composition, which makes it difficult to adjust the solubility (developability) of a cured portion (exposed portion) and an uncured portion (unexposed portion).
(4) when a dye has a low molar absorption coefficient (8), it needs to be used in large amounts, and the amount of other components in the composition, such as a polymerizable compound (monomer), a binder or a photopolymerization initiator need to be reduced. As a result, curability of the colored curable composition, heat resistance after being cured, or developability of the uncured portion, may deteriorate.
As a means for solving the problems caused by the use of a dye, specifically those related to (1) light fastness and heat fastness and (4) molar absorption coefficient (8), use of a dipyrromethene metal complex as a dye has been considered (see, for example, United States Patent Application Laid-Open No. 2008-0076044).
Dipyrromethene metal complexes are known for their excellent light fastness and heat fastness, high molar absorption coefficient and favorable absorption properties in terms of color reproduction (see, for example, United States Patent Application Laid-Open No. 2008-0076044), and are used to produce color filters for liquid crystal display devices or solid-state image sensors (see, for example, United States Patent Application Laid-Open No. 2008-0076044). Dipyrromethene metal complexes are also used as a sensitizer for a radical polymerization initiator in a polymerizable composition that polymerizes with visible light, or as a functional compound of various kinds (see, for example, Japanese Patent No. 3279035, Japanese Patent No. 3324279, JP-A No. 11-3526685, JP-A No. 11-352686, JP-A No. 2000-19729, JP-A No. 2000-19738 and JP-A No. 2002-236360).
Further, in order to improve the solubility or the like, use of a porphyrin compound having a steric parameter of 0.5 or more has been proposed (see, for example, JP-A No. 2005-313632). However, even though the solubility is improved, other properties such as heat fastness are yet to be satisfied.